Machine for trimming and removing braid from shielded wire and cable



1951 J, c. RUPERT 2,573,497

I MACHINE FOR TRIMMING AND REMOVING BRAID FROM SHIELDED WIRE AND CABLEFiled Nov. 13, 9 0

l Inve ntor;

Jack C.Rupert, by m 8% His Attorney. 1

Patented Oct. 30, 1951 MAciIINE FOR TRIMMING AND REMOVING BRAID FROMSHIELDED WIRE AND CABLE Jack C. Rupert, Syracuse, N. Y., assignor toGeneral Electric Company, a corporation of New York Application November13, 1950, Serial No. 195,318

' a 2- Claims.

This invention relates to machines for trimming and removing braid. fromshielded wire and cable to prepare the wire and cable ends forconnection to the terminals of electric circuits.

Heretofore the trimming and removing of braid from shielded wire andcable has been a task performedby hand with the use of knives orscissors. Not only does this hand operation usually result innon-uniform and ragged termination of the shields, but also it oftenresults in injury to the insulation surrounding the wire or cable.Moreover, the. process is time. consuming, particularly since it issometimes necessary to return and straighten the frayed and uneven braidbefore a neat appearing, satisfactory termination can be obtained.

Therefore, it is the object of this invention to provide a machine forquickly trimming and removing braid from shielded wire and cable, whichleaves a neat, even edge and does not damage the insulation.

The device of this invention accomplishes this aim by cutting the braidby means of a shearing action between a stationary knife blade and amovable knife blade. The insulation is kept clear of the shearing zoneby a guide integral with the stationary blade.

For a better and more complete knowledge of this invention referenceshould be made to the following specification together with theaccompanying drawing in which: Fig. 1 is a view partially in section ofa preferred embodiment of this invention and Fig. 2 is an end view takenon a larger scale of a portion of the view shown in Fig. 1.

Referring to Fig. 1, a shaft I has a crank 2 mounted at its end. Thecrank 2 is connected by a crank pin 3 to a bearing block 4. One end of along movable knife blade is secured firmly in a recess 5 in the bearingblock 4 by a rivet I. The

upper portion of the long movable knife blade 5 extends through asupporting block 8 in a slide 9 of rectangular cross-section cuttherein. The end portion of the movable blade 5 which extends beyond thesupporting block 8 contains a recess It, as shown on a larger scale inFig. 2. A short stationary blade II having an end portion I2substantially crescent-shaped is held fixed by a pin I3 in the slide 9of the supporting block 8 juxtaposed to the movable blade 5. The bladesare so positioned relative to each other that the crescent-shaped endportion I2 of the stationary blade I I is adjacent the recess ID in theend portion of the movable blade 5 with the point of the edge of therecess I0. Fig. 2 shows this feature drawn to a larger scale. A springloaded adjusting screw It serves to keep the end portions of the bladestogether;

When shaft 1 is rotated, motion is transmitted through crank 2 andcrankpin 3 to bearing block 6, so that bearing'blockfi moves in acircular path. The end of long movable knife blade 5 attached to bearingblock 4' also assumes a circular motion. The upper portion of movableblade 5, however, can move only in a longitudinal direction since it isconstrained from transverse motion by slide 9 of supporting block 8. Theupper portion of the movable blade including the end portion containingrecess- I0: therefore adopts a reciprocating motion.

The transverse motion of bearing block 4 is absorbed by the spring ofthe portion of movable blade 5 between bearing block 4 and supportingblock 8. As the upper portion of movable blade 5 reciprocates, its endportion containing recess l0 moves up and down past the outer edge ofthe crescent-shaped end portion I2 of stationary blade II, This producesa shearing action between the edge of recess II) of the end portion ofmovable blade 5 and the outside edge of the crescent-shaped end portionI2 of stationary blade I I. The line along which the shearing actionoccurs is hereinafter called the shearing zone. The point of thecrescent-shaped end portion I2 of stationary blade II protrudes beyondthe shearing zone to act as a guide.

To prepare the shielded cable I5 for trimming, a section It of the braidI1 is expanded slightly away from the insulation I8 surrounding theconductors I9 by pushing toward each other the portions of braid I'Iadjacent section I6 on both sides. The expanded section I6 of braid I1is then forced against the point of crescentshaped end portion I2 ofstationary blade I I so that the point penetrates section I6.

To cut braid I1, cable I5 is now rotated in a clockwise direction, asindicated in Fig. 2, bringing the whole circumference of expandedsection I6 into the shearing zone of the blades.

Crescent-shaped end portion I2 of stationary blade II acts as a guide ascable I5 is revolved. Conductor I9 and surrounding insulation I8 arekept separate from braid I! by the point of end portion I2 and pass downand away from the shearing zone as the cable is rotated. Braid I1,however, rides on the upper edge of end portion I2 into the shearingzone at which it is severed. This action of end portion I2 that passesthe concrescentshaped portion l2 protruding b y nd the M ductors andinsulation on the opposite side of blade II from that'at which theshearing action occurs prevents damage to the insulation.

This invention has been described showing one preferred method ofimparting motion to the movable knife blade, but many other methods willgive equally good results. An eccentric system imparting a longitudinalreciprocating motion to the entire movable knife blade is but oneexample. The result necessary is that at least the end portioncontaining the recess, if not all the movable knife blade, move withlongitudinal reciprocating motion. 1

While this invention has beenillustrated and described in connectionwith one preferred em" bodiment thereof, many modifications will occurto those skilled in the art and it will, therefore,

be understood that I intend by the appended claims to cover all suchmodifications as fall within the true spirit and scope of my invention.What I claim as new" and desire to secure by Letters Patent of theUnited States is: 11' A machine for trimming and removing braidfrom'shieldedrwir'e and'cable comprising a Stationary knife blade havingan end portion substantially crescent-shaped, a movable knife bladehaving an end portion provided with a recess, said movable knife bladebeing juxtaposed to said stationary blade to produce a shearing actionbetween the outside edge of said crescent-shaped end portion of saidstationary blade and the edge of said recess of said end portion of saidmovable knife blade upon reciprocating motion of said end portion ofsaid movable knife blade, the point of said crescent-shaped end portionof said stationary blade protruding beyond the zone of said shearinaction to act as a guide, means to support said stationary knife bladeand said movable knife blade, and means to impart a reciprocating motionto said end portion of said movable knife blade.

2. A machine for trimming and removing braid from shielded wire andcable comprising a shaft,

means for rotating said shaft, a crank mounted at the end of said shaftand rotated thereby, a bearing block attached to said crank by a crankpin and actuated thereby, an elongated movable knife blade secured byone end portion to said bearing block and actuated thereby, said movableknife blade having a second end portion provided with a recess, a shortstationary blade having an end portion substantially crescent-shaped, asupporting member constraining a portion of said movable knife blade tomove only a longitudinal direction, said constrained portion includinsaid end portion provided with a recess, said constrained portion havingreciprocating motion upon rotation of said shaft, said supporting memberholding said stationary knife blade juxtaposed to said movable knifeblade to produce a shearing action between the outside edge of saidcrescent shaped end portion and the edge of said recess in said endportion of said movable No references cited.

